He was, in the driver's seat of a skycab, precisely as invisible as The Purloined Letter. But now, if he were to drive his skycab away from the cruising level, he needed one more accessory. He had time. So long as the Military was looking for a Military man in Military surroundings and in a Military manner, he was as safe from detection as if he really owned the skycab he'd commandeered. The civilian police were closer to success. Called by the chief of the arresting party who'd arrived at Gloria Hanford's apartment too late by minutes, the minions of Law and Order converged in their civilian efficiency. Logistically, it was a simple matter of hare and hounds. The hare couldn't win. Only one question was important: Which of the hounds would? Afoot and by jetcopter that englobed the area, they closed in. By the application of stored memory and studied information they erected invisible barriers at every exposed point along the most probable trail of their quarry, from the street outside of her apartment door to the garage stall in Monticello. Then, as a final clincher, they installed three men in Gloria Hanford's airscooter itself. By virtue of the unexpected movement one can elude the cops for a time. Gloria, on the street before her apartment building, almost went into despair when she saw that there was no skycab within hailing distance. She almost took it as a personal affront. But this was hardly the time to stamp her sandals on the hard pavement or to write letters to the Commissioner of Public Carriers. * * * * * She turned and disappeared into the tramway entrance heading North along Waterfront Avenue. Her coin had hardly hit the bottom of its slot when the mobile police converged to land on the spot she'd just vacated. The foremost of them saw her trim figure disappearing into the distance, eclipsed by the myriads of innocent souls whose only desire was to make use of the same Northbound Tramway. The pursuit began to reshape its surface of detection from englobement to a cylinder, the axis of which lay congruent with the Northbound Tramway. Again, she held the advantage of knowing her own decision whereas her pursuit had to divine her plans by analysis of her actions and making use of extrapolation. Gloria Hanford abruptly stepped off the Tramway at Fifty-third, walked briskly three long blocks to LaGuardia's Sixth, found herself facing a group of burly policemen, and stopped long enough to think. One of the cops shoved a galton whistle between his teeth and blew a supersonic blast that registered on every cop's detector within a quarter mile. Audibly a siren wailed. Inaudibly and invisibly the drawstring web of civic forces began to close in.